"Test everything." It's a saying.

<-- Software engineer with particle modeling experience.

 

[quote name='HONDAP1' date='Mar 23 2007, 08:27 PM']Naka is consistent with the literature in"
Going Faster: Master the art of race driving" by the Skip Barber Racing School.

 

^In racecar setup you are not going to be changing the height enough to make any considerable difference in weight proportions without sacrificing suspension geometry and aerodynamics. That is probably why the book says you can't. You will get people too hung up on balancing the car and not the dynamics of the car.

Naka, I would like to see some calculations on changing the front to rear ride height by 1" and what that would do to the front/rear balance (starting with a 50/50 2600lb chassis 94.5" wheelbase). TIA

 

[quote name='rlaifatt' date='Mar 24 2007, 10:39 AM']Actually the opposite.

 

[quote name='l8brakr' date='Mar 24 2007, 12:24 PM']^In racecar setup you are not going to be changing the height enough to make any considerable difference in weight proportions without sacrificing suspension geometry and aerodynamics.

 

Quotes from Going Faster (Skip Barber book, p 211-212):
[

 

And yet, you have me (an aerospace engineer with a degree from MIT) feeling a little dubious about your description.... Seriously, I really appreciate all the feedback I got on this question. Even the stuff I didn't agree with helped because it helped me figure out what I did agree with. But when people start quoting "simple physics" to me, it really raises red flags because I know enough physics to realize that most problems are not simple.

OK, here's what actually happened this past weekend.

Changes:

1) new set of (used) RA1s purchased from Jerry Peterson at the last moment to replace my corded set from the week before

2) different track (Spokane) which has a much better surface

3) tightened up all the shock settings except for front rebound (at the suggestion of 3312DC and the East Coast contingent).

What I had before (turns from full hard, bigger is softer): Front, 1.5 rebound, 0.75 bump; Rear, 2.5 rebound, 0.75 bump

His recommended settings: Front, 1 rebound, 0.5 bump; Rear 1.5 rebound, 0.5 bump

What I did: Front, 1.5 rebound, 0.5 bump; rear 1.5 rebound, 0.5 bump

=======================

Results: The car was worlds better. Didn't hurt turn-in at all, and I had absolutely none of the unstable feeling that I had before. (Nor did I loop it anywhere.)

So, which of those three changes made the difference? Hard to say for sure, but I think it was the shocks that had the most effect. However, it's always possible that it could have been any or all of the three things.

 

first post that has made sense on physics in this thread.

 

[quote name='l8brakr' date='Mar 24 2007, 10:24 AM'] ^In racecar setup you are not going to be changing the height enough to make any considerable difference in weight proportions without sacrificing suspension geometry and aerodynamics.

 

Did you run the old settings on the new track?

If not then i vote for the new track as a very likely 4th possibilty for better behaviour.

If you did run the old settings, were you then able to identify a particular turn(s) on the new track that exhibited the problematic behaviour? Did the changes in settings make the difference you describe on those turns?